In many known rotary machines, the magnetic circuit of the stator is formed by superposing magnetic laminations that are generally annular in shape, each lamination being made by being cut out, with teeth defining intervening slots for passing electrical conductors of a primary or a secondary magnetic circuit.
Application EP-A-0 823 771 describes a stator having one winding on each tooth. The magnetic circuit of the stator is made up by assembling together sectors which define air-gaps halfway across the slots. Subdividing the stator into sectors weakens the stator since the bearing surfaces between the sectors are relatively narrow. Furthermore, the magnetic flux passes through as many air-gaps as there are sectors, thereby reducing the efficiency of the machine.